javax.servlet.jsp.tagext
Class ValidationMessage

As of JSP 2.0, a JSP container must support a jsp:id attribute
to provide higher quality validation errors.
The container will track the JSP pages
as passed to the container, and will assign to each element
a unique "id", which is passed as the value of the jsp:id
attribute. Each XML element in the XML view available will
be extended with this attribute. The TagLibraryValidator
can then use the attribute in one or more ValidationMessage
objects. The container then, in turn, can use these
values to provide more precise information on the location
of an error.

The actual prefix of the id attribute may or may not be
jsp but it will always map to the namespace
http://java.sun.com/JSP/Page. A TagLibraryValidator
implementation must rely on the uri, not the prefix, of the id
attribute.

ValidationMessage

Create a ValidationMessage. The message String should be
non-null. The value of id may be null, if the message
is not specific to any XML element, or if no jsp:id
attributes were passed on. If non-null, the value of
id must be the value of a jsp:id attribute for the PageData
passed into the validate() method.